Landing indicator for aircraft



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R. COU RTOIS-SU FFIT LANDI-NG INDIGATORFOR AIRCRAFT Filed Dec. 20, 191'8 2 sheets-sheet 2 AMHA/n Patented Apr. 3, 1923. l

ROGER COURTOIS-SUFFIT, OF PARIS, FRANCE.

LANDING INDICATOR FOR AIRCRAFT.

`Application filed December 20, 1918. Serial No. 267,634.

To all whom it may concern.'

' Be it known that l, ROGER Courroie-SUF- Frr, citizen of the Republic of France, and resident of Paris, France, (post-oflice address Q Passage du Chemin Vert)` have invented a new and useful Landing Indicator for Aircrafuwhich improvements are fully set forth in the following specification.

This invention relates to landing indicators for use on air craft, enabling the )ilot to gauge the vertical distance of the maclhine from the ground and indicating to him, with the greatest possible precision, the instant at, which his machine should land, without his having to look at the ground. Consequently, in the event of the pilotl being in difficulties when preparing,y to land, owing to inability to see the ground, it will be possible for him to readily determine the proper moment at which to execute t-he necessary straightening-out manuvers.

The improved indicator is chiefly intended for use on dark nights or in foggy weather, when it is sometimes very difficult to gauge the approach of the land.

The invention is based on the theory that a body moving in the air is exposed thereby to aerodynamic reactions, Numerous experiments have shown that these reactions will vary as the body approaches the, ground.

It will be readily understood that under these conditions, if two vertically spaced points are taken on an aircraft, the air pressure at the point placed at the lower level will be less than that at the point placed at the upper level; in other words, the lower point will be more influenced than the upper by the proximity of the ground when the machine approaches the ground. This results in a difference of reactions at these two points, which it will be possible to record.

It will be assumed at. that the two points above referred to are arranged, for example, two pressure funnels or bell mouths. If the actions of these elements are equalized and controlled in'some suitable manner it will be apparent that in the vertical zone adjoining the landing, it will be possible at any moment to readily take a reading of the difference in pressures produced at that moment, and to utilize such reading to deter` mine the distance of the machine from the ground.

The two points at which the tunnels or bell-mouths are 4arranged may be so chosen as to take advantage of the influence that the ground may have on certain parts of an aeroplane flying at a very low height. Thus, if the supporting surface of the machine is influenced by the ground, it may be advisable to place the bottom funnel below the supporting surface or at any other similar suits able point, for the purpose of still further amplifying the difference of effect produced on the two separate funnels by the proximity of the ground.

It is pointed out that pressure funnels or bell mouths are `referred to merely by way of example. They may be replaced by various other devices. i. e., bodies or devices of different shapes capable of transmitting the air reactions and connected together by a suitable transmission gear which may be pneumatic, mechanical, electrical, etc. So also the following description of the complete mechanism is illustrative merely of one embodiment of the invention, based upon the principles above set forth.

ln the accompanying drawing, wherein such embodiment is represented:

Figure l is a side elevation of the indicator;

Figure 2 is a section on line A-B, Figure l; v

Figure 3 is a` front elevation;

Figure 4 is a diagrammatic view showing the indicator installed on a machine, and Figure 5 is Ia fragmental perspective'view of one end of the indicator.

Referring more particularly to the drawing, the two funnels'are indicated at l, l, in Figure 4, and are shown as connected by tubing t, t to the receiver 2. The latter, which is represented in Figures l and 2', comprises an air-tight gear case @,substan-l tially sector-shaped and provided with oppositely-locatedtubular nipples t and f3 to which the ends of the tubes t and if are respectively attached. Thenipple t3 opens into the interior of the gear case C, but the nipple 2 opens intoyan aneroid, cu'pli, the flexible portion or diaphragm of which has connected to its center a lever L. This'lever L is fulcrumed adjacent'its rear end on a bearing and is provided at said end with a laterally offset portion which abuts against a lateral arm m fastened' to a small horiyZontal rock shaft n., which, in turn, 1s suitably journaled within the gear case. Shaft n has fastened to it a second lateral arm mi', the free endA of which bears against the lower edge of a lever al adj'acent the enlarged rear end g thereof. The lever (l is mounted to swing on a pin or tulcrum n', which fits at its ends in seats tormed in a pair ot spaced plates: P and P, arranged within the case, and is located slight-ly beyond the arm m, the tront end ot the lever extending through a longitudinally-slotted, graduated scale c and terminating in a transversely-arranged inde-X finger (t. The scale c is disposedvertically adjacent the large end ot the case C in position to be read through the transparent wall thereot, and is curved to an arc ot which the tulcrum or pivot n constitutes the center, as will be understood. The graduation lilies marked on the scale extend transversely. thereot, and are calculated tor different altitudes to cor-- respond' to the different pressure reactions to which the tunnels are subjected, the lowermost o r zero line being reached by the index finger ay at the very moment when the machine touches lthe ground.

The various parts, as tar as described, act in substantially the tollowing manner: The air pressures exertedupon the aneroid cup b cause its diaphragm member to Hex and, in consequence, draw the lever L inwardly toward it, assuming, ot course, that the machine is descending; .(it the machine is ascending, then the diaphragm will eX in an outward direction or expand, and the lev'er L will be torced away trom the. cup). any case, the movement ot the lever will be I transmitted by its offset end to the arm fm ot the rock shatt n, and trom the latter, through arm m', to the indicator lever el, with the result that said indicator lever will be swung downward, and its finger a will gradually approach 'the lowermost graduation on scale c, reaching the graduation exactly at` the same time that the machine reaches the ground. 'Hence the position ot the index finger upon the scale will constantly indicate the distance ot the machine from the ground, and readings can be taken whenever desired. The indicator lever has a slight tendency toward backward or upward movement, due to the provision ot its enlarged head g, which functions as a weight to correspondingly overbalance the long arm ot the lever.

To enable 'the accurate adjustment ot parts and to compensate tor any errors which may occur by reason ot deviation between the tunnels arising in consequence ot possible dissymmetry ot action or non-similarity ot the zone wherein they are placed, a second aneroid cup b is provided, which communicates with the atmosphere by way ot a tube or nipple e and has connected to it a shutter@ by means ot a suitable coupling L, the latter being located centrally ot the flexible portion or. diaphragm ot the cup and centrally ot the shutter as well. The ends ot the shutter project diametrior area, such, tor example, as dense woods, which will produce the same, or substantially the same effects upon the tunnels as the grounds.A

I claim as my invention l. rthe combination, with an air cratt ot an indicating'apparatus, comprising a pair ot tunnels located at vertically-spaced points onthe air cratt, and' a receiving device withwhich the tunnels are connected and including an indicator adapted to automatically measure the difference ot the aerodynamic pressures to which the tunnels are subjected.

2. The combination, with an air cratt, ot an indicating apparatus, comprising a pair ot tunnels located at vertically-spaced points on the air cratt, and a receiving device with which'the tunnels are connected and including a scale, an indicator member eo-operative therewith` and a lever system tor operating said index member in accordance with the ldifference ot the aerodynamic pressures to which the tunnels are subjected.

The combination, with an air cratt, ot an indicating apparatus, comprising a pair ot tunnels located at vertically-spaced points o n the air cratt, and 'a receiving device with .which the tunnels are connected, said device embodying a diaphragm 4member subjectedl to aerodynamic'stresses at opposite sides and an indicator operatively connected withllsaid diaphragm member.

4. The combination, ot an indicating apparatus, comprising a pair ot tunnels located at vertically-spaced points on the air cratt, and a receiving device with which the tunnels are connected, said device embodying a diaphragm member subjected to aerodynamic stresses at op' posite sides, an indicator lever, a scale along which said lever is arranged to travel, and a lever system connecting 'said diaphragm member and said lever tor operating the latter trom the tormer.

5. The combination, with an air cratt, ot an` indicating apparatus, comprising a pair ot tunnels loca-ted at vertically-spaced points on the air cratt, and a receiving device with which the tunnels are connected and including an indicator tor'automatically measuring the difference ot the aerodynamic pressures to which the tunnels are subjected and with'an air cratt,

means connected with said-indicator to compensate for errors in its measurements.

6. The combination, With an air craft, of an indicating apparatus, comprising a pair of funnels located at vertically-spaced points on the air craft, and a receiving device embodying an air-tight case with the interior of which the funnels Aare in tubular communication and an indicator Within said case adapted to automatically measure the difference of the aerodynamic reactions taking place at said funnels.

7. The combination, with an air craft, oi an Cindicating apparatus, comprising a pair of s funnels located at vertically-spaced points on the air craft, and a receiving device embodying an air-tight case, an aneroid cup within the case, one funnel having a tube leading from it into the interior of said cup, and the other funnel having a tube leading from it and opening into the interior of said case, an indicator within said case and operatively associated with said cup for automatically measuring the difference of the aerodynamic pressures to Which the funnels are subjected, and means connected with said indicator to compensate for errors in its measurements. l

In testimony whereof I have signedthis specification in the presence of two subscribing Witnesses.

ROGER COURTOIS-SUFFIT.

Witnesses:

JOHN F. SIMoNs, GEORGE LoIsEL. 

